In recent years, remarkable efforts have been made in the sensous aspect of goods for increasing the added value thereof, for example, by upgrading the visual appeal, in addition to upgrading the substantial aspect of goods, such as an improvement of their physical properties, etc.
However, up to now, a technique for printing a design of a satisfactory appearance on a preformed component or stock is not readily available. As a method of patterning a molded component having desired shape and consisting of a wide variety of stock material, a method is known, for example, which comprises floating a desired pattern on the surface of water, placing said component on said pattern, forcing said component down under the surface of water thereby applying said pattern to the surface of said component by water pressure, and drying to impart a similar effect to printing. This method, has problems in productivity and the outward appearance of the resulting product has a so-called flat appearance, which make said method unsatisfactory.
With the upgrading of construction materials in recent years, many approaches have been tried in an effort to impart a pattern to molded components of hydraulically setting materials such as plaster of paris, cement, etc. so as to enhance the value.
Japanese Patent Laid Open 52965/77, for example, discloses a method of in-mold decorating comprised of printing a decorative pattern on a sheet using a water soluble ink, molding said sheet to a desired form, casting a slurry of hydraulically setting material to cure said material, while transferring said printed pattern to the surface of the hydraulically cured material by dissolving out the water soluble ink. This method has many advantages. However, prior methods including the above method have serious drawbacks. One of said drawbacks of the above-mentioned Japanese Patent Laid Open application, for example, is a lack of water resistance because of the use of water soluble ink and thus upon immersion in water, the decorative pattern disappears, which imposes a severe limitation in the application of said printed material and also which makes it unsuitable to use as a construction material. On the other hand, if a decorative delicate rock vein is printed on a material, especially on a hydraulically cured component by a prevailing method such as the thermographic transfer process or sublimation transfer process, the printed decorative pattern has a drawback in the difficulty in reproducing a sharp high fidelity rock vein due to the propensity towards obscuring of the printed pattern, which comes from the poor deposition of ink.
Flexographic printing using rubber plates is suited to the printing of wood veins but has similar defect in the printing of rock veins.